1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
|
/* ****************************************************************************
*
* Copyright (c) Microsoft Corporation.
*
* This source code is subject to terms and conditions of the Microsoft Public License. A
* copy of the license can be found in the License.html file at the root of this distribution. If
* you cannot locate the Microsoft Public License, please send an email to
* dlr@microsoft.com. By using this source code in any fashion, you are agreeing to be bound
* by the terms of the Microsoft Public License.
*
* You must not remove this notice, or any other, from this software.
*
*
* ***************************************************************************/
using System;
using System.Diagnostics;
using System.Linq.Expressions;
using System.Reflection;
using System.Reflection.Emit;
using System.Runtime.CompilerServices;
namespace Microsoft.Scripting.Generation {
/// <summary>
/// Provides a simple expression which enables embedding FieldBuilder's
/// in an AST before the type is complete.
/// </summary>
public class FieldBuilderExpression : Expression {
private readonly FieldBuilder _builder;
#if SILVERLIGHT
private readonly StrongBox<Type> _finishedType;
// Silverlight doesn't have ModuleInfo.ResolveField so we need to
// get something which can be updated w/ the final type instead.
public FieldBuilderExpression(FieldBuilder builder, StrongBox<Type> finishedType) {
_builder = builder;
_finishedType = finishedType;
}
#else
public FieldBuilderExpression(FieldBuilder builder) {
_builder = builder;
}
#endif
public override bool CanReduce {
get {
return true;
}
}
public sealed override ExpressionType NodeType {
get { return ExpressionType.Extension; }
}
public sealed override Type Type {
get { return _builder.FieldType; }
}
public override Expression Reduce() {
FieldInfo fi = GetFieldInfo();
Debug.Assert(fi.Name == _builder.Name);
return Expression.Field(
null,
fi
);
}
private FieldInfo GetFieldInfo() {
// turn the field builder back into a FieldInfo
#if SILVERLIGHT
return _finishedType.Value.GetField(_builder.Name);
#else
return _builder.DeclaringType.Module.ResolveField(
_builder.GetToken().Token
);
#endif
}
protected override Expression VisitChildren(ExpressionVisitor visitor) {
return this;
}
}
}
|
